Spacer spraying system, spacer spraying method and liquid crystal display panel

ABSTRACT

A spacer spraying system and spacer spraying method are provided which are capable of spraying spacers uniformly in a liquid crystal display panel forming region on a substrate. A stage includes a main stage section having a predetermined size and an auxiliary stage section supported in the main stage section so as to be slid in the main stage section or another auxiliary stage section having a structure in which the auxiliary stage section can be connected to the main stage section. By making the auxiliary stage section be slid in the main stage section or be connected to the main stage section according to a size of a substrate mounted on the stage, a size of the stage is made changeable so that a distance between an edge portion of the stage and a liquid crystal display panel forming region existing near the edge portion of the stage falls within a predetermined range.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/191,974, filed Jul. 29, 2005, which claims priority from JapanesePatent Application Number 2004-221637, filed Jul. 29, 2004, the contentsof all of which are incorporated herein by reference

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a manufacturing device andmanufacturing method for a liquid crystal display panel and a liquidcrystal display panel and more particularly to a spacer spraying systemto spray spacers on a substrate of a liquid crystal display panel and amethod for spraying the spacers on the liquid crystal display panelsubstrate and to a liquid crystal display panel having the liquidcrystal display panel substrate manufactured by using the above spacerspraying system and the above method.

The present application claims priority of Japanese Patent ApplicationNo. 2004-221637 filed on Jul. 29, 2004, which is hereby incorporated byreference.

2. Description of First Related Art

A liquid crystal display panel is widely used as a display device for anAV (Audio-Visual) apparatus, an OA (Office Automation) apparatus, and alike due to its advantages of being thin, light weight, low in powerconsumption, and a like. The liquid crystal display panel of this typeis made up of a TFT (Thin Film Transistor) substrate in which switchingelements such as TFTs or a like are formed in a matrix form and a facingsubstrate in which a color filter, black matrix, or a like are formed.Insulating spacers made of polymer beads, silica beads, or a like, eachhaving a specified size are arranged between both the substrates to forma gap having a specified size which is filled with a liquid crystalsealed hermitically therein. The liquid crystal display panel is soconfigured that an image is displayed by applying a voltage to anelectrode formed on a pair of substrates facing each other or on one ofthe substrates to generate an electric field and by controlling anorientational direction of the liquid crystal according to the electricfield to change transmitivity of light. In the liquid crystal displaypanel having such configurations as above, it is important that, inorder to improve displaying quality, the gap between substrates facingeach other is formed uniformly and, therefore, the spacers used to formthe gap are sprayed uniformly on the substrates.

There are two methods of spraying the spacers on the substrates; one isa wet spraying method in which a spacer-containing solvent obtained bydispersing the spacers in the solvent for example flon (fluoro carbon),alcohol, or a like is jetted from a nozzle and the other is a dryspraying method in which the spacers are charged by an electrostaticcharge process using an electrostatic gun or contact friction and thecharged spacers are jetted from the nozzle. In the case of the wetspraying method, collection of flon, alcohol, or a like is required andthe spacers are easily condensed in the solvent and, therefore, it isdifficult to spray the spacers uniformly on the substrate and, as aresult, the dry spraying method is widely used.

In the case of the dry spraying method, in ordinary cases, the spacersare positively charged and a repulsive force is exerted among thespacers and, therefore, partial condensation of the spacers does notoccur, however, since a central portion of a stage is locatedimmediately below the nozzle, an amount of the sprayed spacers tends toincrease. On the other hand, since a distance between a peripheral edgeportion of the stage and the nozzle increases at the central portion ofa stage, the amount of the sprayed spacers tends to decrease at theperipheral edge portion of the stage, thus causing the sprayed spacersto be not uniform in a density distribution on an entire of the stagedepending on a positional relation between the nozzle and the stage.

In order to improve such uniformity of a spacer spray densitydistribution caused by the positional relation between the nozzle andthe stage, a method is disclosed in which a chamber of a spacer sprayingsystem is charged so as to have a potential with the same polarity(positive polarity in ordinary cases) as that of the charged spacers,and the charged spacers being released in a direction of a charged wallof the chamber with the same polarity as the charged spacers arerepelled from the charged wall of the chamber to a direction of thestage, thus enabling the spray density of the spacers to be distributeduniformly. For example, in Japanese Patent Application Laid-open No.2002-148635, a spacer spraying system is disclosed in which a sprayingchamber housing a substrate has a layer-stacked structure in which eachlayer is electrically insulated and a voltage having a potential withthe same polarity as that of the spacers is applied from an outside tothe most inner layer surface of the chamber to make the spacerstravelling on surfaces of the chamber be repelled by the electrostaticforce, thus enabling a amount of the sprayed spacers in a peripheraledge portion of the substrate to be reduced.

Though non-uniformity in a density distribution of the sprayed spacerscaused by the positional relation between the above nozzle and the stagecan be improved by using the spacer spraying system disclosed in theJapanese Patent Application Laid-open No. 2002-148635, the amount of thespacers that gather around the peripheral edge portion of the stage byelectrostatic repulsion from the chamber wall increase. To solve thisproblem, by adjusting a level of a voltage to be applied to a wallsurface of the chamber and/or by improving a shape of a nozzle used tospray the spacers or a spray pattern of spacers or a like, amounts ofthe sprayed spacers in the peripheral edge portion of the stage placednear the chamber wall are calibrated, however, even if such adjustmentsare made, it is impossible to uniformly control the density distributionof the sprayed spacers on the substrate.

The reason for the above is that the density distribution of the sprayedspacers is varied not only by a positional relation between the nozzleand the stage and/or the positional relation between the chamber walland the stage but also by the positional relation between the stage andthe substrate placed on the stage. More particularly, though an electricfield is approximately constant in a central portion of the stage, theelectric field is concentrated in an edge portion of the stage due to anedge effect, which causes the amount of the sprayed spacers to increasein the peripheral edge portion of the substrate located near the edgeportion of the stage.

In the case where the liquid crystal display panel is small in size orthere is a sufficient space in a position where the substrate is cut(that is, in the case where an interval between the liquid crystaldisplay panels is large when a plurality of the liquid crystal displaypanels is produced by one piece of the substrate), since a distancebetween the edge portion of the substrate and the region where theliquid crystal display panel is formed can be made large, even if thespraying amounts of the spacers increase due to the edge effect, theinfluence caused by the increased amounts of the spacers can be madesmall in the region where the liquid crystal display device is formed.However, when the liquid crystal display panel is large in size and whenmany liquid crystal display panels are densely arranged on the substrateto achieve reduction in costs, inevitably, no sufficient space exists inthe position where the substrate is cut and, as a result, the influencecaused by the edge effect occurs even in the liquid crystal displaypanel forming region being located in the vicinity of the stage end.

In order to reduce the influence caused by the edge effect, a method isavailable in which the substrate is located far from the stage end bymaking the chamber or the stage larger in size. However, if the chamberis larger in size, the amount of the spacers that can be used during aone-time spacer spraying process increases, causing unnecessaryconsumption of high-priced spacers and an increase in costs in themanufacturing of the liquid crystal display panel. Moreover, a size ofthe liquid crystal display panel varies depending on each of productsrequired by users and, if a distance between the stage end and theliquid crystal display panel forming region being located in thevicinity of the stage end also varies depending on each of the products,the spacer spraying density changes in every product and, as a result,variations in performance of the product occur.

3. Description of Second Related Art

As explained in the first related art, when a liquid crystal displaypanel is manufactured, it is of importance that a gap between a pair ofsubstrates facing each other is uniform and, to achieve this, uniformspraying of spacers on surfaces of the substrates is required.Therefore, in the spacer spraying system of a type that applies avoltage to a chamber, by adjusting a level of a voltage to be applied toan inner wall of the chamber and by improving a shape of a nozzle to jetspacers or a pattern of spraying spacers, uniformity of sprayed spacersin a density distribution is improved.

For example, in a conventional spacer spraying system having dimensionsas shown in FIG. 13A, when a voltage to be applied to an inner wall ofthe chamber is set at 4.0 kV, 7.0 kV, and 10 kV and a spraying mode foreach of the voltages is set at a mode 2 and mode 3 as shown in FIG. 13B,respectively, spraying density of spacers corresponding to each distancefrom a substrate end is as shown in FIG. 14. Though the spacer spraydensity distribution can be changed by varying the applying voltage orthe spraying mode, if the voltage on a wall surface of the chamber ismade large (see, for example, “X” mark or “*” mark in FIG. 14), sprayingdensity at the substrate end becomes larger. If the voltage on the wallof the chamber is made smaller (see triangular marks in black), thoughspraying density at the substrate end can be made somewhat smaller,spraying density in a position on an inner side of the substrate end(for example, 200 mm to 300 mm from the substrate end) becomes verysmall and, as a result, uniform distribution of the sprayed spacerscannot be obtained at any voltage and the tendency cannot be changed bya change in the spraying mode. The reason for that is that, in themethod in which a voltage to be applied to the chamber inner wall isadjusted and/or a shape of the nozzle or a pattern of spraying spacersis improved, variations in spraying density caused by a positionalrelation between the nozzle and stage or between the chamber wallsurface and the stage are merely reduced, and it is impossible to reducevariations caused by a positional relation between the stage andsubstrate formed on the stage, that is, variations in the spacerspraying density caused by concentration of an electric field at thestage end cannot be reduced.

Moreover, a method is proposed in which, by changing a voltage to beapplied to a stage on which a substrate is formed, variations inspraying density of spacers are reduced. For example, a method isdisclosed in Japanese Patent Application Laid-open No. 2000-275652 inwhich the stage is divided into a plurality of portions of the stage andeach of the divided stages or each of some divided groups of the stagesis set at a different potential. However, the purpose of the methoddisclosed in the above patent application is to improve distribution ofspacers sprayed within an inner surface of the entire stage and,therefore, it is impossible to reduce variations in spacer sprayingdensity caused by a positional relation between the stage and substrateformed on the stage, that is, variations in spacer spraying densitycaused by concentration of an electric field at an edge portion of thestage cannot be suppressed.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention toprovide a spacer spraying system which is capable of spraying spacersuniformly in a region where a liquid crystal display panel is formed,irrespective of a size of the liquid crystal display panel and/or anarrangement of the liquid crystal display panel on a substrate, a methodfor the spraying spacers and the liquid crystal display panelmanufactured by using the above spacer spraying system and/or the abovespacer spraying method.

According to a first aspect of the present invention, there is provideda spacer spraying system including a spraying nozzle, a chamber, and astage being supported within the chamber, for spraying spacers onto asubstrate placed on the stage by using the spraying nozzle,

wherein the stage includes a main stage section having a predeterminedsize and at least one auxiliary stage section associated with the mainstage section, in such a manner that the stage is extendable to adesired size.

According to a second aspect of the present invention, there is provideda spacer spraying system including a spraying nozzle, a chamber, and astage being supported within the chamber, for spraying spacers onto asubstrate placed on the stage by using the spraying nozzle including:

a main stage section having a predetermined size, at outer edge portionof which at least one first attachment portion is provided; and

a plurality of auxiliary stage sections each having a different size,and at inner edge portion of each of which at least one secondattachment portion is provided;

wherein an auxiliary stage section selected arbitrarily out of theplurality of the auxiliary stage sections is attached to the main stagesection, by associating the at least one second attachment portion ofthe auxiliary stage section with the at least one first attachmentportion of the main stage section, whereby the stage is extendable to adesired size.

According to a third aspect of the present invention, there is provideda spacer spraying system including a spraying nozzle, a chamber, and astage being supported within the chamber, for spraying spacers onto asubstrate placed on the stage by using the spraying nozzle,

wherein the stage includes a main stage section having a predeterminedsize and at least one auxiliary stage section being attached to the mainstage section in such a manner that the at least one auxiliary stagesection slides out from the main stage section in a direction parallelto a main face of the main stage section, whereby the stage isextendable to a desired size.

In the foregoing third aspect, a preferable mode is one wherein theauxiliary stage section is supported in a manner in which an upper faceof the auxiliary stage section comes into contact with a lower face ofthe main stage section in a hit state and wherein the spacers depositedon an upper face of the auxiliary stage section are removed by makingthe auxiliary stage section be slid in a direction of the main stagesection.

In the first, second and third aspects, a preferable mode is one whereinan insulator is placed between the main stage section and the auxiliarystage section so that the main stage section and the auxiliary stagesection have electric potentials being different from each other.

Also, a preferable mode is one wherein the substrate is provided with aplurality of regions in each of which a liquid crystal display panel isformed and wherein the auxiliary stage section is associated with themain stage section, so that a distance between a peripheral edge portionof the stage and each of the regions existing near the peripheral edgeportion of the stage falls within a predetermined range.

According to a fourth aspect of the present invention, there is provideda method for spraying spacers onto a substrate placed on a stage beingsupported in a chamber by using a spraying nozzle including the stepsof:

assembling the stage from a main stage section having a predeterminedsize and at least one auxiliary stage section associated with the mainstage section in such a manner that the stage is extendable to a desiredsize; and

adjusting a size of the stage according to a size of the substrate tocontrol density distribution of the sprayed spacers.

According to a fifth aspect of the present invention, there is provideda method for spraying spacers onto a substrate placed on a stage beingsupported in a chamber by using a spraying nozzle including the stepsof:

preparing a main stage section having a predetermined size, at outeredge portion of which at least one first attachment portion is provided;

preparing a plurality of auxiliary stage sections each having adifferent size, and at inner edge portion of each of which at least onesecond attachment portion is provided;

selecting one out of the plurality of the auxiliary stage sectionsaccording to a size of the substrate;

assembling the stage from a main stage section and the selectedauxiliary stage section, thereby controlling density distribution of thesprayed spacers.

According to a sixth aspect of the present invention, there is provideda method for spraying spacers onto a substrate placed on a stage beingsupported in a chamber by using a spraying nozzle including the stepsof:

assembling the stage from a main stage section having a predeterminedsize and at least one auxiliary stage section being attached to the mainstage section in such a manner that the at least one auxiliary stagesection slides out from the main stage section in a direction parallelto a main face of the main stage section; and

adjusting a size of the stage according to a size of the substrate, bysliding out the at least one auxiliary stage section slides out from themain stage section, thereby controlling density distribution of thesprayed spacers.

In the foregoing sixth aspect, a preferable mode is one wherein theauxiliary stage section is supported in a manner in which an upper faceof the auxiliary stage section comes into contact with a correspondingportion of the main stage section and wherein, after the spacers aresprayed onto the substrate, the spacers deposited on an upper face ofthe auxiliary stage section are removed or scraped by making theauxiliary stage section slide out from the main stage section, and themethod for spraying spacers is repeated for a substrate placed newly onthe stage.

In the fourth, fifth and sixth aspects, a preferable mode is onewherein, by placing an insulator between the main stage section and theauxiliary stage section and by applying a predetermined voltage to theauxiliary stage section using a voltage applying unit, a potential beingdifferent between the main stage section and the auxiliary stage sectionis set to control density distribution of the sprayed spacers.

Also, a preferable mode is one wherein the substrate has a plurality ofregions in each of which a liquid crystal display panel is formed andwherein the auxiliary stage section is associated with the main stagesection, so that a distance between a peripheral edge portion of thestage and each of the regions existing near the peripheral edge portionof the stage falls within a predetermined range.

According to a seventh aspect of the present invention, there isprovided a liquid crystal display panel in which spacers are sprayed onat least one of a pair of substrates facing each other by using thespacer spraying system described above and/or the spacer spraying methoddescribed above.

With the above configurations, the spacers can be uniformly sprayed inthe liquid crystal display panel forming region on the substrate. Thereason is that the stage of the spacer spraying system to be used forthe manufacturing of the liquid crystal display panel is made up of themain stage section being fixed to the chamber and the auxiliary stagesection in a manner in which the auxiliary stage section is able to beslid in the main stage section or of the main stage section to be fixedto the chamber and the auxiliary stage section having a structure inwhich the auxiliary stage section is able to be connected to the mainstage section and a stage size is able to be changed so that a distancebetween the edge portion of the stage and the liquid crystal displaypanel forming region existing near the edge portion of the stage bymaking the auxiliary stage section be slid according to a size of theliquid crystal display panel substrate to be mounted on the stage or byconnecting the auxiliary stage section to the main stage section. Thisenables improvement of uniformity of the spacer spraying density and themanufacturing of the liquid crystal display panel of high displayingquality with a high yield and at low costs obtained by controlling thegap between a pair of the substrates facing each other so as to beuniform, irrespective of a size of the liquid crystal display paneland/or an arrangement of the liquid crystal display panel mounted on thesubstrate. Also, by configuring as above, uniformity of spraying densityof the spacers can be improved and the liquid crystal display panelhaving high displaying quality in which the gap between the pair of thesubstrates facing each other is uniformly controlled can be manufacturedwith a high yield and at low costs.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages, and features of the presentinvention will be more apparent from the following description taken inconjunction with the accompanying drawings in which:

FIG. 1 is a diagram schematically for showing configurations of a spacerspraying system of a first embodiment of the present invention;

FIGS. 2A, 2B, and 2C are diagrams schematically illustratingconfigurations (state in which an auxiliary portion is mounted) of astage of the spacer spraying system of the first embodiment of thepresent invention;

FIGS. 3A, 3B, and 3C are diagrams schematically illustratingconfigurations (state in which the auxiliary portion is slid) of thestage of the spacer spraying system of the first embodiment of thepresent invention;

FIGS. 4A and 4B are diagrams schematically illustrating configurationsof the stage (state in which the substrate is formed on the stage of thespacer spraying system) according to the first embodiment of the presentinvention;

FIGS. 5A, 5B, 5C, and 5D are diagrams illustrating variations of theconfigurations of the stage of the spacer spraying system of the firstembodiment of the present invention;

FIGS. 6A, 6B, and 6C are diagrams illustrating variations of theconfigurations of the stage of the spacer spraying system of the firstembodiment of the present invention;

FIGS. 7A and 7B are diagrams illustrating variations of theconfigurations of the stage of the spacer spraying system of the firstembodiment of the present invention;

FIGS. 8A and 8B are diagrams illustrating variations of theconfigurations of the stage of the spacer spraying system of the firstembodiment of the present invention;

FIGS. 9A and 9B are diagrams schematically illustrating a method forremoving spacers deposited on the stage of the spacer spraying system ofthe first embodiment of the present invention;

FIG. 10 is a graph explaining an effect of the spacer spraying system ofthe first embodiment of the present invention which shows a correlationbetween an edge portion of the stage and an edge portion of thesubstrate according to the first embodiment of the present invention;

FIGS. 11A, 11B, and 11C are diagrams schematically showingconfigurations of a stage of a spacer spraying system of a secondembodiment of the present invention;

FIGS. 12A and 12B are diagrams showing variations of a stage of thespacer spraying system of the second embodiment of the presentinvention;

FIG. 13A is a diagram explaining a positional relation between achamber, a stage, and a substrate employed in a conventional spacerspraying system and FIG. 13B is a diagram explaining a spraying modeemployed in the conventional spacer spraying system; and

FIG. 14 is a graph showing a correlation among a chamber wall surfacevoltage, spraying mode, and distribution of the number of spacers on asubstrate in a conventional spacer spraying system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Best modes of carrying out the present invention will be described infurther detail using various embodiments with reference to theaccompanying drawings.

To solve such a problem as described in the second related art, theinventor of the present invention takes note of the positional relationbetween the stage and the substrate formed on the stage. That is, theinventor has found that, by setting a distance between a stage end and aregion in which a liquid crystal display panel on a substrate is formedwithin a specified range, variations in spraying density of spacerscaused by concentration of an electric field in the stage end can bereduced and a structure in which a size of a stage is changeabledepending on a size of the substrate is obtained based on the knowledge.The structure is described by referring drawings shown below.

First Embodiment

Configurations of a spacer spraying system and spacer spraying method,and a liquid crystal display panel manufactured using the spacerspraying system are described by referring to FIG. 1 to FIG. 10.

FIG. 1 is a diagram for schematically illustrating configurations of thespacer spraying system of a first embodiment of the present invention.FIGS. 2A, 2B, and 2C are diagrams schematically illustratingconfigurations of a stage of the spacer spraying system. FIGS. 3A, 3B,and 3C are diagrams schematically illustrating configurations of thestage of the spacer spraying system. FIGS. 4A and 4B are diagramsschematically illustrating a state in which the substrate is formed onthe stage of the spacer spraying system. FIGS. 5A to 8B are diagramsillustrating variations of the configurations of the stage of the spacerspraying system. FIGS. 9A and 9B are diagrams schematically illustratinga method for removing spacers deposited on the stage of the spacerspraying system. FIG. 10 is a graph explaining an effect of the spacerspraying system, which shows variation in spacer spray density inrelation to a position where a glass substrate is placed on the stage ofthe spacer spraying system.

As shown in FIG. 1, the spacer spraying system 1 of the first embodimentof the present invention chiefly includes a chamber 2 which is heldinternally in a state of a reduced pressure by a damper 8, an exhaustduct 9, or a like, a stage 3 whose size is adjustable which is a featureof the embodiment, a nozzle which sprays positively or negativelycharged spacers on a substrate (for example, a TFT substrate or a facingsubstrate making up a liquid crystal display panel) 10 placed on thestage 3, a spacer feeding section 6 which feeds spacers to the nozzle 4,a transport pipe 5, and a high voltage source 7 to set the chamber 2 ata specified potential. After the substrate 10 on which spacers are to besprayed is placed on the stage 3, pressure inside the chamber 2 isreduced by using the damper 8 and the exhaust duct 9 and, if necessary,a voltage having the same potential as that of the spacers is applied tothe chamber 2 by using the high voltage source 7 and the spacers fedfrom the spacer feeding section 6 via the transport pipe 5 are jettedthrough the nozzle 4 to make the spacers be deposited on the substrate10. Moreover, in FIG. 1, the spacer spraying system 1 of a type thatapplies a voltage to the chamber 2 is shown, however, a spacer sprayingsystem of a type that does not apply a voltage to the chamber 2 may beused and, in this case, the high voltage source 7 is not required.

In ordinary cases, the spacers are positively charged and the nozzle 4used to jet spacers is also positively charged while the stage 3 isgrounded and, therefore, an electric field occurs between the nozzle 4and stage 3, which guides the spacers to the substrate on the stage 3.However, the intensity of the electric field is not uniform on the stage3 and the electric field is concentrated due to an edge effect at anedge portion of the stage 3, thus causing an amount of sprayed spacersto increase. Furthermore, when a pulse voltage is applied to the chamber2, the spacers repelled at the chamber 2 come flying to the stage 3 and,therefore, an peripheral edge portion of the stage 3 is changed to be aregion (called a “spacer-excessively-sprayed region”) where the amountof sprayed spacers becomes excessive.

According to experiments made by the inventor, it has been found thatthe “spacer-excessively-sprayed region” is located within a specifieddistance range from the edge portion of the stage 3 and, therefore, bymaking a liquid crystal display panel forming region on the substrate 10be positioned, to some extent, far from the edge portion of the stage 3,variations in the amount of sprayed spacers in the liquid crystaldisplay panel forming region can be reduced. Thus, in the embodiment ofthe present invention, by configuring the stage 3 so that a size of thestage 3 can be adjusted and changed, and so that the size of the stage 3can vary depending on a size of the substrate 10 to be placed on thestage 3, the “spacer-excessively-sprayed region” and the liquid crystaldisplay panel forming region on the substrate 10 do not overlap.

Concrete structures of the stage 3 are described by referring to FIGS.2A, 2B, and 2C and FIGS. 3A, 3B, and 3C. FIG. 2A and FIG. 3A are planviews seen from an upper portion of the stage (from a side of the nozzle4) and FIG. 2B and FIG. 3B are cross-sectional views taken along a lineA-A′ and B-B′, respectively, and FIGS. 2C and 3C are side views seenfrom a direction of the arrow.

As shown in FIGS. 2A, 2B, and 2C, the stage 3 of the embodiment includesa main stage section (stage proper) 3 a to be fixed to the chamber 2 andan auxiliary stage section 3 b to be housed so as to be able to be slidin/out in a direction parallel to the main face of the main stagesection 3 a. As shown in FIGS. 3A, 3B, and 3C, the stage 3 is soconfigured as to be changed to obtain a desired enlarged size by slidingout the auxiliary stage section 3 b from the main stage section 3 a.

Moreover, in FIGS. 2A, 2B, and 2C and 3A, 3B, and 3C, as the stagehaving the simplest configurations, the stage is provided which hasconfigurations in which the auxiliary stage section 3 b is housed in thespace formed in the main stage section 3 a and slides out from the mainstage section 3 a by a manual means. However, the configurations of thestage 3 are not limited to those shown in FIGS. 2A, 2B, and 2C and 3A,3B, and 3C. That is, any configuration may be used so long as at least apart of the auxiliary stage section 3 b is supported by the main stagesection 3 a and the main stage section 3 a and auxiliary stage section 3b make up the stage 3 having a desired size. The configurations forhousing the auxiliary stage section 3 b, its housing location, slidingstructure of the auxiliary stage section 3 b, existence or non-existenceof the stopper, a width, length, thickness, or a like of the main stagesection 3 a and the auxiliary stage section 3 b can be changed whenevernecessary. For example, as shown in FIGS. 7A and 7B, configurations inwhich the auxiliary stage section 3 b is slid out/in by rotating atoothed gear 12 b may be employed. Moreover, in FIGS. 7A and 7B, theauxiliary stage section 3 b is housed in both right and left directionson sides of the main stage section 3 a, however, the auxiliary stagesection 3 b may be housed in at least one side of the main stage section3 a. Furthermore, the auxiliary stage section 3 b may be housed in bothup-down and right-left directions in the main stage section 3 a.

In the above embodiment, the main stage section 3 a is grounded so thatspacers positively charged can be guided effectively into the stage 3and, therefore, the auxiliary stage section 3 b is made up of a metalmaterial (preferably being the same material as that of the main stagesection 3 a) and the main stage section 3 a and auxiliary stage section3 b are electrically connected so that the auxiliary stage section 3 band main stage section 3 a are at the same potential. However, the mainstage section 3 a is not necessarily required to be connected directlyto the auxiliary stage section 3 b and the main stage section 3 a andauxiliary stage section 3 b may be separately grounded.

Next, a state in which the substrate 10 is placed on the stage 3 havingthe adjustable-size structure is described by referring to FIGS. 4A and4B. FIG. 4A is a top view illustrating a state in which the substrate 10is placed on the main stage section 3 a housing the auxiliary stagesection 3 b and FIG. 4B is a top view illustrating a state in which theauxiliary stage section 3 b is drawn from the main stage section 3.

For example, in the case in which liquid crystal display panel formingregions 10 a are rectangular and spacers are sprayed on the substrate 10on which the liquid crystal display panel forming regions 10 a arealigned in three rows and three columns, since, if the main stagesection 3 a is square as shown in FIG. 4A, a distance between an edgeportion of the main stage section 3 a and an edge portion of each of theliquid crystal display panel forming regions 10 a located in thevicinity of the edge portion of the main stage section 3 a in adirection parallel to each of short sides of the liquid crystal displaypanel forming regions 10 a is sufficiently long, there is no problemthat spacer spray density distribution does not becomes uniform.However, since a distance between the edge portion of the main stagesection 3 a and a peripheral edge portion of each of the liquid crystaldisplay panel forming regions 10 a in a direction parallel to each oflong sides of the liquid crystal display panel forming regions 10 a isshort, there occurs a problem that the spacer spray density distributiondoes not become uniform. To solve this problem, as shown in FIG. 4 b, bydrawing the auxiliary stage section 3 b from the main stage section 3 a,the stage 3 is expanded, as a whole, in a direction of each of the longsides of the liquid crystal display panel forming regions 10 a. Byconfiguring as above, the distance between the edge portion of theauxiliary stage section 3 b and the peripheral edge portion of theliquid crystal display panel forming regions 10 a located in thevicinity of the edge portion of the auxiliary stage section 3 b can bemade sufficiently long, thus preventing the problem that the spacerspray density distribution becomes non-uniform.

In order to confirm an effect obtained by changing a size of the abovestage 3, by changing an interval between the edge portion of the stage 3and edge portion of the substrate 10, the number of spacers sprayed onthe substrate 10 in each state is measured. FIG. 10 shows the results.FIG. 10 shows the distribution of the number of sprayed spacers obtainedwhen a distance between the edge portion of the stage 3 and edge portionof the substrate 10 is set at 10 mm, 30 mm, and 50 mm in the spacerspraying system 1 having the chamber 2 being 1680 mm×1680 mm in size andthe chamber 3 being 1330 mm×1330 mm in size.

In FIG. 10, if the distance between the edge portion of the stage 3 andedge portion of the substrate 10 is 10 mm (shown by triangular marks inblack and a dashed line), the number of sprayed spacers is as large as348 pieces per unit area when the distance from the edge portion of thesubstrate 10 is 10 mm. Then, as the distance from the edge portion ofthe substrate 10 becomes longer, the number of sprayed spacers graduallybecomes smaller. However, if a targeted number of the sprayed spacers isset at about 200 pieces, its lower limit is set at about 150 pieces, andits upper limit is set at about 250 pieces, the number of sprayedspacers exceeds a tolerance until the distance from the substrate 10reaches 50 mm. Moreover, when the distance between the edge portion ofthe stage 3 and the edge portion of the substrate 10 is 30 mm (shown byrectangular marks in black and a broken line), the number of sprayedspacers is lowered to be 298 pieces when the distance from the edgeportion of the substrate 10 is 10 mm, however, the number exceeds thetolerance till the distance from the edge portion of the substrate 10reaches 30 mm. On the other hand, when the distance between the edgeportion of the stage 3 and edge portion of the substrate 10 is 50 mm(shown by circular marks in black and a solid line), the number ofsprayed spacers is 254 pieces which falls approximately within atolerance when the distance from the edge portion of the substrate 10 is10 mm. Therefore, by drawing the auxiliary stage section 3 b so that thenumber of sprayed spacers falls within a tolerance required actually bya spacer spraying system being commercially available, the influencecaused by the edge portion of the stage 3 can be reduced to a degree towhich no problem occurs substantially.

Moreover, it is impossible to strictly define a desirable distancebetween the edge portion of the stage 3 and edge portion of the liquidcrystal display panel forming region 10 a located in the vicinity of thestage 3 since the distance varies depending on a shape of the chamber 2or the nozzle 4 in the spacer spraying system 1, a spraying pattern ofspacers, a voltage to be applied to the chamber 2, charged voltages ofspacers, a shape of the stage 3, or a like. However, in the case of thespace spraying device 1 in which a distance between the nozzle 4 andstage 3 is, for example, 1550 mm and a distance between the edge portionof the stage 3 and an inner wall of the chamber 2 is, for example, 175mm, it is confirmed that, by setting the distance between the edgeportion of the stage 3 and edge portion of the liquid crystal displaypanel forming region 10 a at about 50 mm to about 130 mm, an amount ofsprayed spacers can be fallen within a desirable range in an entire ofthe liquid crystal display panel forming region 10 a on the substrate10.

In FIGS. 2A, 2B, and 2C and in FIGS. 3A, 3B, and 3C, the structure isprovided in which the auxiliary stage section 3 b is drawn from the mainstage section 3 a and, therefore, a difference in height occurs betweenthe main stage section 3 a and auxiliary stage section 3 b and there isa problem that variations in spraying density of spacers occur caused byconcentration of an electric field on the portion having a difference inheight. To prevent the occurrence of such a difference in height, ataper portion 11 may be provided at the edge portion of the main stagesection 3 a, as shown in FIG. 5A, or a taper portion 11 may be providedat the edge portion of the auxiliary stage section 3 b, as shown in FIG.5D, and, by configuring as above, an unnecessary difference in heightcan be eliminated and the concentration of the electric field can besuppressed. Moreover, as necessary, a preferable shape of the tapersection 11 and a preferable taper angle may be employed. In FIGS. 5B and5D, a cross-sectional shape of the taper portion 11 is in a form of astraight line, however, may be rounded off so that its thicknesschanges. Also, the taper portion 11 may be provided in even a side onwhich the auxiliary stage section 3 b is not mounted in the same manneras above.

Also, in FIGS. 2A, 2B, and 2C to FIGS. 5A, 5B, 5C, and 5D, the structureis shown in which the auxiliary stage section 3 b is slid out from themain stage section 3 a so that the stage 3 can be extended essentially.However, another structure may be employed in which the auxiliary stagesection 3 b is supported in the main stage section 3 a so that theauxiliary stage section 3 b is made rotational by using a hinge (notshown) and, when a size of the stage 3 is to be made larger, by rotatingthe auxiliary stage section 3 b using the hinge as a shaft, theauxiliary stage section 3 b is connected to a side face of the mainstage section 3 a.

The above structure has a characteristic that a size of the stage 3cannot be continuously variable, however, it is possible to eliminate adifference in height between the main stage section 3 a and theauxiliary stage section 3 b to become equal in height for the entirestage 3.

Also, still another structure may be used, as a structure to change asize of the stage 3, in which a convex portion (guide portion 12 a)serving as a guide for drawing the auxiliary stage section 3 b from themain stage section 3 is formed on the main stage section 3 a as shown inFIGS. 6A, 6B, and 6C and a concave portion having a specified size at aplace corresponding to the convex portion is formed. By configuring asabove, the size of the auxiliary stage section 3 b is made the same asthat of a side of the main stage section 3 a and, therefore, the stage 3becomes rectangular which can suppress deviation in an electric field.Also, as shown in FIGS. 2A, 2B, and 2C to FIGS. 6A, 6B, and 6C, thestructure in which the auxiliary stage section 3 b slides out from themain stage section 3 a by a manual means so that the stage 3 isextendable is provided. However, as shown in FIG. 7, still anotherstructure may be employed in which a toothed gear 12 b is attached to aside or a like of the main stage section 3 a so as to be rotational and,on the other hand, convex and concave portions each having a shape thatengages in the toothed gear 12 b are formed in a portion that comes intocontact with the toothed gear 12 b at the bottom surface of theauxiliary stage section 3 b, thus enabling the auxiliary stage section 3b to be slid out in a direction parallel to a main face of the stage 3by rotating the toothed gear 12 b. By configuring as above, amounts ofdrawing the auxiliary stage section 3 b can be controlled accurately anda size of the stage 3 can be automatically adjusted by rotating thetoothed gear 12 b using a motor or a like.

Moreover, since it is anticipated that an electric field distributionchanges at time of drawing the auxiliary stage section 3 b and, as aresult, distribution of sprayed density of spacers is changed and,before spacers are sprayed on the substrate 10 on which the liquidcrystal display panel is formed, the distribution of the sprayingdensity of spacers is measured in advance and, according to the result,amounts of drawing the auxiliary stage section 3 b can be finelyadjusted. In this case, the spraying density of spacers may be measuredby any type of method. For example, probes at specified intervals in thevicinity of the stage 3 are mounted and, by using this probe, chargedspacers are detected and, based on potentials of the probes, displayingdensity of spacers existing in that place can be estimated. Also, amagnetic field generated by movements of charge spaces is measured byusing a Hall device and, based on current values of the Hall device,spraying density of spacers occurring in that place is estimated.Furthermore, light is irradiated from an upper portion of the stage andlight reflected by the stage or test substrate is measured by using alight detecting means and, based on an output from the light detectingmeans, spraying density of spacers is obtained. Thus, by mounting thespacer spraying density measuring means such as a probe, Hall device, ora like as described above in advance on the spacer spraying system 1, anamount of drawing the auxiliary stage section 3 b can be set moreaccurately.

Also, in FIGS. 2A to 2C and FIGS. 7A and 7B, the main stage section 3 aand the auxiliary stage section 3 b are electrically connected to eachother and are set at the same potential (here, ground potential),however, may be set at a potential being different from each other. Forexample, as shown in FIGS. 8A and 8B, the main stage section 3 a and theauxiliary stage section 3 b are insulated using an insulator 14 fromeach other and the main stage section 3 a is grounded and a potential ofthe auxiliary stage section 3 b may be set by using a voltage adjustingsection 13 mounted in advance. If a result about the spacer sprayingdensity obtained by using the above methods shows that the spacerspraying density at an edge portion of the substrate 10 is large, bymaking a voltage of the auxiliary stage section 3 b be nearer to that ofthe spacers, uniformity of the spacer spraying density can be improvedfurther.

Moreover, it is anticipated that repeated use of the spacer sprayingsystem 1 causes deposition of the spacer on the stage 3 on the auxiliarystage section 3 b in particular at every spraying process and the stage3 is covered with an insulator and, as a result, electric fielddistribution in the stage 3 changes and repeatability of the spacerdistribution cannot be obtained. However, in the structures shown inFIGS. 2A to 2C and FIGS. 8A and 8B, the auxiliary stage section 3 b issupported by the main stage section 3 a in a manner in which theauxiliary stage section 3 b can be inserted or drawn to and from themain stage section 3 a and, therefore, by setting sizes in a manner inwhich an upper face of the auxiliary stage section 3 b comes in contactstraight with a lower face (the insulator 14 in FIGS. 8A and 8B) of themain stage section 3 a as shown in FIGS. 9A and 9B and, when theauxiliary stage section 3 b is housed in the main stage section 3 aafter the completion of spraying of the spacers 15, the spacers 15deposited on the auxiliary stage section 3 b can be collected and can beremoved from the auxiliary stage section 3 b and, therefore, a surfaceof the auxiliary stage section 3 b can be cleaned simply, thus enablingaccurate control of the spacer spraying density.

Thus, since the stage 3 of the spacer spraying system 1 of theembodiment of the present invention is made up of the main stage section3 a fixed to the chamber 2 and the auxiliary stage section 3 b beinghoused in the main stage section 3 a in a manner in which the auxiliarystage section 3 b is slid in the main stage section 3 a, the auxiliarystage section 3 b can be drawn according to a size of the substrate 10being mounted on the stage 3 and a distance between the edge portion ofthe stage 3 and edge portion of the liquid crystal display panel formingregion 10 a of the substrate 10 can be set within a predetermined range,thereby enabling an influence by the edge portion of the stage 3 to beavoided and uniformity of the spacer spraying density to be improved.Moreover, since it is possible to set the size of the stage 3 to bearbitrary, irrespective of a size of the substrate 10 or a position ofcutting the substrate 10, an optimum spacer spraying density can beobtained all the time.

Second Embodiment

A spacer spraying system and a spacer spraying method of a secondembodiment of the present invention and a liquid crystal display panelmanufactured by the spacer spraying system are described by referring toFIGS. 11A, 11B, and 11C and FIGS. 12A and 12B, which are diagramsshowing configurations of a stage of the spacer spraying system.

In the first embodiment of the present invention, the stage 3 is made upof the main stage section 3 a and the auxiliary stage section 3 b beingso configured as to be slid in the main stage section 3 a. However, inthe structure in which the auxiliary stage section 3 b is drawn out fromthe main stage section 3 a, a difference in height easily occurs in aconnected portion between the main stage section 3 a and auxiliary stagesection 3 b and configurations of the stage 3 becomes complicated. Onthe other hand, a size of the liquid crystal display panel and itscutting positions are not so many. To solve this problem, according tothe second embodiment, the size of the stage 3 is not adjusted in anarbitrary manner by sliding the auxiliary stage section 3 b but changedby connecting the auxiliary stage section 3 b being mounted, in advance,to the main stage section 3 a.

More specifically, as shown in FIGS. 11A, 11B, and 11C, the stage 3according to the second embodiment of the present invention is made upof a main stage section 3 a fixed to the chamber 2 and having astructure in which an auxiliary stage section 3 b can be attached to atleast a part of an outer edge portion of the main stage section 3 a (oneof connecting means connected to each other) and one or a plurality oftypes of auxiliary stage section 3 b having a structure in which theauxiliary stage section 3 b can be connected to at least a part of aninternal edge section of the main stage section 3 a and, by fitting theauxiliary stage section 3 b from an upper portion of the main stagesection 3 a, the main stage section 3 a is connected to the auxiliarystage section 3 b and, as a result, the stage 3 having a desired sizecan be formed.

In FIGS. 11A, 11B, and 11C, the convex portion is formed in the lowerportion of the main stage section 3 a and another convex portion isformed also in the upper portion of the auxiliary stage section 3 b andthe two convex portions come into contact with each other and, as aresult, the auxiliary stage section 3 b is made to be connected to themain stage section 3 a. However, the main stage section 3 a is connectedto the auxiliary stage section 3 b in an arbitrary manner and, forexample, as shown in FIGS. 12A and 12B, the convex portion (or concaveportion) is formed in at least a part of an outer edge portion of themain stage section 3 a and a concave portion (or convex portion) to befitted into the convex portion (or concave portion) is formed in atleast a part of the inner edge portion of the auxiliary stage section 3b and, by fitting these convex or concave portions, connection of themain stage section 3 a and auxiliary stage section 3 b may beestablished. Moreover, in FIGS. 12A and 12B, the auxiliary stage section3 b is connected to two sides in upper and lower portions of the mainstage section 3 a. However, the auxiliary stage section 3 b may beconnected to at least one side of the main stage section 3 a. Forexample, the concave portion is formed in all the peripheral edgeportions of the main stage section 3 a and the auxiliary stage section 3b is formed in a manner to correspond to each side and the auxiliarystage section 3 b may be connected to only a portion of the stage 3whose size is desired to be changed.

Moreover, also in the second embodiment, in order to measure variationsin the distribution of the number of spacers caused by attachment of theauxiliary stage section 3 b, a spacer spraying amount measuring meanssuch as a probe, Hall device, or a like as described above may bemounted in the spacer spraying system 1 in advance. The main stagesection 3 a and the auxiliary stage section 3 b may be set at the samepotential and, when the influence by the edge portion of the stage 3 isfinely controlled, the auxiliary stage section 3 b may be set at apotential being different from that of the main stage section 3 a.Furthermore, in the second embodiment, the auxiliary stage section 3 bis so configured as to be removable and, after the completion ofspraying the spacers once, only the auxiliary stage section 3 b may bedetached from the main stage section 3 a to be cleaned and, therefore,fluctuations of an electric field caused by deposition of spacers can besuppressed, thus enabling spacer spraying density to be accuratelycontrolled.

Thus, according to the second embodiment, the auxiliary stage section 3b selected in a manner to correspond to a size of the substrate 10 to bemounted on the stage 3 can be connected to the main stage section 3 aand the distance between the edge portion of the stage 3 and the edgeportion of each of the liquid crystal display panel forming regions 10 aon the substrate 10 can be set within a predetermined range and,therefore, variations in the spacer density distribution caused byconcentration of an electric field in the edge portion of the stage 3can be suppressed and, irrespective of a size of substrate 10 and/or acutting position on the substrate 10, distribution of spacers can bekept in an optimum state all the time.

Moreover, in the case where the auxiliary stage section 3 b is attachedto the main stage section 3 a, a difference in height between the mainstage section 3 a and auxiliary stage section 3 b can be eliminated and,therefore, an electric field is not concentrated in a portion where themain stage section 3 a is connected to the auxiliary stage section 3 b,thus enabling more exact control on spacer spraying density. Also, inthe case of the above first embodiment, the auxiliary stage section 3 bis slid in the main stage section 3 a and, as a result, structurally,there is a portion where the auxiliary stage section 3 b is not placedin a corner of the main stage section 3 a. However, in the case of thesecond embodiment, the auxiliary stage section 3 b is connected to themain stage section 3 a and, therefore, the stage 3, as a whole, can bemade rectangular with the auxiliary stage section 3 b being connected tothe main stage section 3 a, thus enabling exact control on the spacerspraying density.

As described above, according to the embodiments of the presentinvention, the stage of the spacer spraying system to be used formanufacturing of the liquid crystal display panel includes the mainstage section to be fixed to the chamber and the auxiliary stage sectionhaving the structure in which the auxiliary stage section is supportedso as to be able to be slid in the main stage section or in which theauxiliary stage section is able to be connected to the main stagesection and the size of the stage is made changeable according to a sizeof the substrate placed on the stage so that a distance between an edgeportion of the stage and a liquid crystal display panel forming regionexisting near to the edge portion of the stage at the edge portion ofthe stage can be reduced. This enables improvement of uniformity ofspacer spraying density and manufacturing of the liquid crystal displaypanel of high displaying quality at a high yield and low costs obtainedby controlling the gap between a pair of substrates facing each other soas to be uniformed.

It is apparent that the present invention is not limited to the aboveembodiments but may be changed and modified without departing from thescope and spirit of the invention. The present invention is applied toany liquid crystal display panel having a structure in which a liquidcrystal is put between two pieces of substrates facing each other. Thatis, the present invention can be applied to any type of liquid crystaldisplay panel including a TN (Twisted Nematic) -type liquid crystaldisplay panel in which a transparent electrode is formed in each ofsubstrates and a liquid crystal is driven by an electric field in alongitudinal direction between the substrates, an IPS (In PlaneSwitching) -type liquid crystal display panel in which a comb-toothedlike electrode is formed on one of the substrates and a liquid crystalis driven by an electric field between the substrates, or a like. Thespacer spraying system and the spacer spraying method can be applied notonly to the substrates to be used for a liquid crystal display panel butalso to any substrate.

1. A spacer spraying system comprising a spraying nozzle, a chamber, anda stage being supported within said chamber, for spraying spacers onto asubstrate placed on said stage by using said spraying nozzle comprising:a main stage section having a predetermined size, at outer edge portionof which at least one first attachment portion is provided; and aplurality of auxiliary stage sections each having a different size, andat inner edge portion of each of which at least one second attachmentportion is provided; wherein an auxiliary stage section selectedarbitrarily out of said plurality of said auxiliary stage sections isattached to said main stage section, by associating said at least onesecond attachment portion of said auxiliary stage section with said atleast one first attachment portion of said main stage section, wherebysaid stage is extendable to a desired size.
 2. The spacer sprayingsystem according to claim 1, wherein an insulator is placed between saidmain stage section and said auxiliary stage section so that said mainstage section and said auxiliary stage section have electric potentialsbeing different from each other.
 3. The spacer spraying system accordingto claim 1, wherein said substrate is provided with a plurality ofregions in each of which a liquid crystal display panel is formed andwherein said auxiliary stage section is selected so that a distancebetween a peripheral edge portion of said stage and each of said regionsexisting near the peripheral edge portion of said stage falls within apredetermined range.
 4. A liquid crystal display panel in which thespacers are sprayed on at least one of a pair of substrates facing eachother by using the spacer spraying system stated in claim 1.